Reaction propelling device with supercharged engine



22, 1944- I R. ANXIONNAZ ETAL 2,356,557

.REACTION PROPELLING DEVICE WITH SUPERCHARGED ENGINE Filed Nov. 28, 19402 Sheets-Sheet l (endure/er OOdOOO Q a {W (arburr/er IN Vf/V 70R 5ATTORNFY g- 1944- R. ANXIONNAZ ETAL 2,356,557

REACTION PROPELLING DEVICE WITH SUPERGHARGED ENGINE Filed NOV. 28, 19402 Sheets-Sheet 2 n K! rr rr r O o 'o o o o \x \x xx \x ,3 z (arbure/cr Hu 6 r1 I! n fig 8 e x y w d ]1 g (ardareii r ATTORNEY Patented Aug. 22,1944 REACTION PROPELLING DEVICE WITH SUPERCHARGED ENGINE Rene Anxionnaz,Paris, and Roger Imbert, Mantes, France; vested in the Alien PropertyCustodian Application November 28, 1940, SerialNo. 367,667

In France December 19, 1939 4 Claims. (Cl. 6035.6)

The supercharging units of aviation engines, which are constituted by aturbine driven by the exhaust gases and actuating a compressor, are nowcapable of a very high efllciency. It follows (I that the power that canbe supplied by the gas turbine exceeds what is strictly necessary fordriving the compressor. In order to restore the power balance, a portionof the gases have been evacuated into the atmosphere, or a supplementaryresistance has been created by a governor, but these arrangementsinvolve a loss of energy.

It has also been endeavored to utilize this excess of power byintensifying the scavenging of the engine, which has been brought up to60 per cent and even more, but the advantage of this operation is verysmall because the gain of power which results therefrom for the engineis negligible.

The object of the present invention is to utilize this excess of energyof the exhaust gases with the maximum efllciency in order to improve thepropelling eifect applied to the airplane, which is tatamount to amaterial increase of the output of the motor-propeller unit.

According to the essential feature of the present invention, we combinea thermal engine with a turbine operated by the exhaust gases anddriving a supercharging compressor and with a reaction nozzle.

This arrangement permits of utilizingln the reaction nozzle the excessof power of the exhaust gases with a very high output, even when thespeed of the airplane is relatively low. It even permits of increasingthe power of the motor-propeller system without modifying the engine orthe fuel consumption thereof, by slightly increasing the exhaustcounter-pressure. Finally, it makes it possible to obtain a goodregulation of the main engine without loss of power so that said enginecan thus preserve its maximum efficiency for all values of the powerdeveloped.

Other features of the present invention will result from the followingdetailed description of some specific embodiments thereof.

Preferred embodiments of the present invention will be hereinafterdescribed, with reference to the accompanying drawings, given merely byway of example, and in which:

Fig. 1 shows the general arrangement of an aviation engine system madeaccording to the present invention; 7

Fig. 2 is a diagrammatical view showing a device for controlling thesection of the nozzle above referred to;

Figs. 3 and 4 are views, similar to Fig. 2 showing modifications.

Fig. 5 shows a modification in which are illustrated regulating meansfor the gas streams;

Fig. 6' shows an embodiment of the invention provided with an airby-pass leading to a point behind the gas turbine;

Fig. 7 shows an embodiment in which the compressor is divided into twoportions;

Fig. 8 is a view similar to Fig. 7, showing a modification; and

Fig. 9 shows an embodiment in which air is fed to the reaction nozzlewithout compressor.

Fig. 1 shows an aviation engine a, which, in this case is supposed to beof the usual gasoline type, with a carbureter, but which might also beof any other type, either of the explosion or com-. bustion kind.

Compressor 0 receives air at e through an orifice which is preferablyturned in the direction in which the airplane is travelling, in order totake advantage of the compression created by the relative velocity ofair. It discharges this compressed air to the suction side of theengine, through the carbureter j of any known type.

The exhaust gases from the engine, which are at a pressure higher thanatmospheric pressure at the height at which the airplane is travelling,are brought to the gas turbine d, where they expand in the distributingnozzles and drive wheel h. When leaving said turbine the gases againexpand in reaction nozzle g, which is turned in the direction opposed tothat in which the airplane is travelling. The gases thus produce, owingto the relatively high velocity they have, a driving impulse on theairplane. This action is equal to the product of the mass of gasdelivered per second by their relative outlet velocity.

The chief advantage of this arrangement is that it produces a usefulwork which serves to the propulsion of the airplane, whereas thecorresponding loss produced by counter-pressure at the exhaust is muchlower. This results from the following calculation:

Considering for instance the case of an engine of 1000 H. P., having ascavenged volume of 600 liters per second, it is known that the output,

of the exhaust gases of this engine is approximately 1000 grammes persecond. If the airplane is flying at a height of 5000 metres,corresponding to an atmospheric pressure of .0.5 kg. per squarecentimeter, the excessive pressure necessary for imparting to thesegases, which are supposed to be at a temperature of 500? C.,

a velocity of 300 meters per second is about 0.091 kg. The thrustproduced by these gases is then:

1 F= mX V=mX300-30.6 kgs.

It the airplane is moving with a velocity of 150 5 meters per second,that is to say 540 kilometers per hour, the useful work produced bythisthrust hich gives 582 km, or about 8 H. P.

Thus,the application of the reaction nozzle inthiscaseensuresa gainofpower whichis quite substantial in comparison with the results obtainedby means of the devices used at the 28 present time. Furthermore, thepresence of the nozzle ensures an easy self-regulation of the propeliingsystem. It suiilces to provide the reaction nozzle with a device forvarying the section of the outlet orifice thereof. It is thus possible30 to vary the coimter-pressure created by this nozzle, and, therefore,the flow through the gas turbine for a given pressure.

This arrangement has the same advantages as the arrangement which wouldconsist in varying the section of the distributing nozzles of the gasturbine but it has the great advantage that it can be operated inflight, owing to a control placed under reach of the pilot's hand.

This results from the following considerations: If the pilot increasesthe section of the nozzle, the counter-pressure produced by said nozzleis reduced. Consequently, the output of the gas turbine will tend toincrease for anunchanged pressure supplied by the compressor therefore,as the driving power of the turbine comes to exceed the resisting powerof the compressor, the turbo-blower unit will tend to accelerate andthus increase the supercharging of the proso polling engine, whichpermits of increasing the power supplied by said engine when thethrottle valve of carbureter f has already been, for instance, fullyopened. on the contrary, the same operation in the reversed way, that,is to say u the reduction of the section. of nozzles g, red the powersupplied by engine a.

This regulation of power takes place under truly economical conditions,because if the carbureter throttle valve remains fully opened, despitethe reduction of the power of the engine, this avoids the losses bywiredrawlng which would otherwisetakeplace ifthethrottlewerepartlyclosed,andtheeiliciencyoithe propelling engine remains practicallyconstant.

This arrangemmt is particularly advantageous when itia with theprovision of a bypassconnectingtogethertheintakeandtheexhaustoftheengineasshowninflgjat b.

Various means may be employed for varying-thesectionoffl1coutletnonle.1"igs.2,3and4 show some of thesearrangements.

Intheembodimentofl'lmlapieceiof pointedshapeisplacedinthecentraipartofthcnoatrolled by the pilot throughsuitable means, when moving forward piece 1 toward the aperture ofnozzle g, the section of said aperture is reduced, and-inversely.

In the embodiment of Fig. 3, the nozzle 0 is divided into a plurality ofelementary nozzles by means of blades 1. A movable shutter m operated bythe pilot through any suitable control means permits of obturating avariable number of nozzles formed between blades 1. I thus obtain,according to the number of elementary nozzles left in operation, anadjustment of the section of nozzle 0. I

In the embodiment of Fig. 4, the principle is the same, but shutter m isof circular section and pivots about an axis 0. Owing to the circularshape of the shutter m the resultant of the forces, produced by thedifference ofthe pressures existing on the respective faces of theshutter, intersects the axis 0. The said forces are thus without effecton the moving of the shutter, which is extremely easy.

In all cases, nozzle g is suitably directed, so that the jet of gasescaping through the nozzle is turned in the direction opposed to thedirection of travel of the airplane.

Fig. 5 shows various other adjustment means.

First, the pilot can operate the throttle valve 9 provided on the intakeand which may be combined with carbureter f. It is also possible toprovide a control valve q in bypass b, so as to create a diiference ofpressure between the d18- charge of the compressor and the intake of thegas turbine, which thus produces an unbalance of the power of these twoelements and consequently involves the acceleration of the .group whenvalve q opens and a slowing down when it closes.

Furthermore, we may place, on the intake 0! the gas turbine or on theexhaust of engine a,

1 a discharge into the atmosphere, 1', provided with an adjustment valves. When this valve is opened, a portion of the gases is deviated fromthe turbine, which therefore tends to reduce the speed of the turbineand consequently the supercharging of the engine.

In order to avoid completely loss of the gases thus discharged into theatmosphere, when the discharge port is to be opened for a long time. itis possible to return the discharged gases into nozzle 0, but behind thturbine. The gases can thus expand in said nozzle, adding theirpropelling eifect to that of the gases which have passed through theturbine. This arrangement is the one shown by Fig. 5.

As the eihciency of the reaction turbine is the higher as the velocityof the. gases which escape I therefrom is closer to the velocity of themovement of the airplane, and as the velocity of the gases is as a rulemuch higher than that of the airplane, it is advantageous, in order toimprove the emciency, to produce in the reaction nozzle only arelatively small expansion, which, therefore, corresponds to arelatively low drop of a temperature of the gases.

As the exhaust gases of the engine are very hot, they carry along withthem into the atmos- 'phere a relatively important amount of heat, whichis thus lost. In order to recuperate a portion of the powercorresponding to this heat, the exhaust gases. upon leaving the gasturbine, may be mixed with a certain amount of air, previouslycompressed but which has not flowed through the engine. 'This air isheated by its mixzleanditcanbemovedthmugharodkcon- 16 ingwiththegscs,anditexpandsinthenozale together with said gases, which improves thepropelling efiect.

This air may be obtained at the outlet of the supercharging compressor,as shown by Fig. 6. In this embodiment, the compressor is of the axialtype, with helicoidal wheels t1, t2, t3 and guides ui, uz. The airenters at e in a duct e1 comprising a forwardly facing entry part ezwith a divergent form and a rearwardly facing reaction nozzle g with aconvergent form. The air entering at e is compressed by the compressorand is collected at the outlet in tore-shaped conduits 12 which leads itto the intake of engine a. The discharge or exhaust of the engine isconnected with the nozzles d of the gas turbine h and upon leaving saidturbine, the exhaust gases are mixed with the, cold air directlydischarged by the compressor through conduit 10. This mixture of air andgas then expands in nozzle g to produce the reaction effect.

It may be of interest, in order to obtain a good emciency, to collectthe air which is 'not toflow through the engine at a pressure lower thanthat necessary for the supercharging of the engine. This results fromthe fact that, as above stated, the pressure that can be utilized innozzle g is relatively low. Consequently, when the compressor is of themulti-stage type, it will be advantageous to take the air in questionfrom anintermediate stage. Such an arrangement is shown by Fig. '7. Inthis embodiment, the compressor is divided into two parts the first ofwhich, 1:, acts on the whole of the air that is drawn in. This air issubsequently divided into two streams, one of which passes through thesecond part, 12 of the compressor and serves to the supercharging of theengine. The exhaust gases from said engine drive turbine h and, uponleaving said turbine, are mixed with the cold air from compressor stage:c, which flows directly through conduits w. The mixture expands innozzle g and produces th propelling effect.

In view of the diiference of output and of pressure that is necessaryfor the two compression stages a: and y, it may be advantageous toconstitute them by machines running at different speeds. Fig. 8 shows anarrangement of this kind in which compressor 1! is driven directly bygas turbine 71., for instance through a shaft common to both of them,while compressor a: is driven through a gear train 2 which makes itpossible to drive it at a different speed better adapted to thecharacteristics required therefrom.

As the drop of pressure utilized in the reaction nozzle is relativelylow, the additional air may also be supplied by the very displacement ofthe airplane in the atmosphere, without making use of a compressor. Theair from the atmosphere enters, owing to its relative velocity, throughan inlet orifice e' of the rear portion of the duct system designated w(Fig. 9) in which a portion of its kinetic energy is transformed intopressure.

It mixes with the hot gases coming from theexhaust of the turbine, whichraise its temperature; then it e pands, together with said gases, innozzle 9.

This produces a positive work, although the expansion is in this caseequal only to the relative velocity of the inflowing air, because, inthe meantime the air has been heated and the speed it acquires in nozzle9 for a given expansion is the higher as its temperature is higher. Thisarrangement might even be employed in the case of an engine which is notsupercharged, in which the heating of the air would be directly producedby mixing with the exhaust gases from the engine.

In a general manner, while we have, in the above description, disclosedwhat we deem to be practical and eflicient embodiment of the presentinvention, it should be well understood that We do not wish to belimited thereto as there might be changes made in the arrangement,disposition and form of the. parts without departing from the principleof the present invention as comprehended within the scope of theappended claims.

What we claim is: a

1. In combination with an aircraft engine 'which is adapted to receivesupercharging air and which discharges its exhaust gases at asubstantially controlled pressure, a-motive unit to supply superchargingair to the engine by extracting energy from exhaust gases and also toexert an auxiliary propelling force for assisting in driving theaircraft comprising, a shroud structur extending parallel to thedirection of flight adjacent the aircraft engine and 'having at itsforward end an air inlet and at its trailing end a jet outlet, acompressor case positioned within said shroud structure and having anouter surface corresponding to the inner surface of the shroud structurebut spaced therefrom whereby a substantially annular passage-way isprovided for the passage of the air through the shroud structure aboutthe compressor case, a rotary.

air compressor mounted within the forward end of said annularpassage-way and effective to partially compress the air passing throughsaid passage-way, a second compressor positioned in trailingrelationship with respectto the firstnamed compressor to receive. aportion of the partially compressed air discharged therefrom and todeliver its compressed air to the engine, a turbine connected to driveboth of said compressors positioned in trailing relationship withrespect to the second-named compressor and to receive exhaust gases fromthe engine, said tur- I said shroud structure has a shroud structure toexert a propelling force.

2. Apparatus as described in claim 1 wherein both of said compressorsand said turbine are mounted in alignment upon a single rigid shaft.

3. Apparatus as described in claim 1 wherein both of said compressorsand said turbine are mounted in alignment and said second turbine isgeared to the first-named turbine through a gear reduction assembly.

4. Apparatus as described in claim 1 wherein divergent inlet and RENEAmoNNAz. ROGER mam.

a convergent outlet.

